JP3776158B2

JP3776158B2 - Safety shoe tip and method for manufacturing the same

Info

Publication number: JP3776158B2
Application number: JP07526496A
Authority: JP
Inventors: 祥雅桜井
Original assignee: Midori Anzen Co Ltd
Current assignee: Midori Anzen Co Ltd
Priority date: 1996-03-04
Filing date: 1996-03-04
Publication date: 2006-05-17
Anticipated expiration: 2016-03-04
Also published as: JPH09238708A

Description

【０００１】
【発明の属する技術分野】
本発明は、着用者の足先を圧迫及び衝撃から保護するために、安全靴の足先に装着する安全靴用先芯及びその製造方法に関するものである。
【０００２】
【従来の技術】
従来、この種の安全靴用先芯の耐圧迫性及び耐衝撃性は、日本工業規格（ＪＩＳ）により規定され、例えば重作業用及び普通作業用の革製安全靴では金属材料を用いること、そして軽作業用の革製安全靴には金属材料又は合成樹脂材料を用いることとされている。
【０００３】
一般に、合成樹脂は繊維により強化される場合が多く、先芯はこれらの合成樹脂や繊維を用いて射出成形又は圧縮成形により成形される。例えば図６に示すように、先芯１にはアーチ状の先芯本体部２と、この先芯本体部２の下辺から内方に折曲され略円弧状に突出する下辺折曲部３とが設けられる。そして、先芯１を射出成形する場合には、成形を容易にするために金型のゲートを先芯本体部２の後端中央部２ａ又は後端側部２ｂに設ける場合が多く、金型のランナーは複数個取りを行うために短くする場合が多い。
【０００４】
このように成形された先芯１は、日本工業規格に応じた圧迫試験及び衝撃試験が行われる。圧迫試験は先芯１に対して図示しない加圧ベッドにより所定の荷重を徐々に加えることにより行われる。また、図７に示すように、衝撃試験においては衝撃刃Ｃを有するプランジャＰを先芯１の上面に配置し、このプランジャＰの上に所定重量の重錘を所定の高さから落下させることにより行われる。
【０００５】
【発明が解決しようとする課題】
しかしながら上述した従来例では、先芯本体部２の後端中央部２ａに金型ゲートを設けた場合には、射出成型時に合成樹脂や繊維は図８に示すように金型空洞内で先芯１の天壁に相当する部分から先芯１の前壁及び両側壁に相当する部分に向かって流れ、先芯１の両側壁に相当する部分では合成樹脂や繊維の流れは垂直方向の配向になる。このため、上方からの耐圧迫性は充足しても、その前壁や両側壁では合成樹脂や繊維が衝撃刃Ｃの方向と同様な配向になるため、耐衝撃性が不足するという問題がある。
【０００６】
また、図９に示すように後端側部２ｂに設けた金型ゲートから合成樹脂や繊維を注入すると、合成樹脂や繊維は先芯１の一方の側壁に相当する部分から先芯１の天壁及び前壁に相当する部分に向かって流れ、その後に先芯１の他方の側壁に相当する部分に流れる。このため、合成樹脂や繊維が先芯１の天壁、前壁及び両側壁で衝撃刃Ｃと直交する方向に配向するので、耐衝撃性を充足するものの、耐圧迫性が不足するという問題がある。
【０００７】
更に、金型ゲートを先芯本体部２の後端中央部２ａ及び後端側部２ｂに設けた場合には、先芯１の形状や肉厚に起因するものと思料される合成樹脂や繊維の合流によるウエルドラインが発生する場合が多いために、使用中に圧迫や衝撃を受けた場合に、切断部５に応力が集中して先芯１に亀裂が発生するという問題もある。
【０００８】
そして、先芯１を成形した後に、図１０に示すように金型のランナーに残存したランナー相当部４を切断部５において切断し仕上げ加工をする必要がある。この仕上げ加工が十分でない場合には、安全靴の着用者に違和感を与えたり、外観不良を起こしたりするという問題がある。
【０００９】
また、品質の観点から先芯１は後端に向かって徐々に薄くされている反面で、その強度を向上させるために、前壁の厚さｔや、先芯本体部２と下辺折曲部３の連接部の曲率Ｒを大きくする場合がある。しかしながら、この場合にも合成樹脂や繊維の配向を変化させることはできず、ウエルドラインや亀裂の発生も防止できないという問題もある。
【００１０】
本発明の目的は、上述した問題点を解消し、合成樹脂の流れの配向をなくして耐圧迫性や耐衝撃性を向上させた安全靴用先芯及びその製造方法を提供することにある。
【００１１】
【課題を解決するための手段】
上記目的を達成するための第１発明に係る安全靴用先芯は、足先部に装着して足先を保護するためのアーチ型の先芯本体部と、該先芯本体部の下辺から内方に略円弧状に突出する下辺折曲部とを有する合成樹脂製の安全靴用先芯において、成型時における前記合成樹脂の注入口を前記下辺折曲部の内縁の略中央に相当する位置に設け、前記注入口から前記合成樹脂を金型空洞の前壁に衝突するように射出成型したことを特徴とする。
【００１２】
また、第２発明に係る安全靴用先芯の製造方法は、足先部に装着して足先を保護するためのアーチ型の先芯本体部と、該先芯本体部の下辺から内方略円弧状に突出する下辺折曲部とを有する合成樹脂製の安全靴用先芯を金型を用いて射出成型により製造する場合において、前記下辺折曲部の内縁の略中央に相当する位置に設けた金型ゲートから前記合成樹脂を金型空洞の前壁に衝突するように射出し、前記合成樹脂の流れを乱すことにより乱流を起こさせて成型することを特徴とする。
【００１３】
【発明の実施の形態】
本発明を図１〜図５に図示の実施例に基づいて詳細に説明する。
図１は本実施例に係る先芯１１を使用した安全靴の一部を切欠した断面図であり、先芯１１は安全靴の足先部に内設されている。表底１２の上部には甲革１３が被着され、表底１２の上面には中底１４が積層され、先芯１１及び甲革１３の底辺は表底１２と中底１４の間に挟持され、先芯１１の内面には先裏１５が貼着されている。
【００１４】
先芯１１は合成樹脂材料により射出成形され、図２の斜視図、図３の縦断面図に示すように、先芯１１には足先を覆うアーチ状の先芯本体部２１と、この先芯本体部２１の下辺から内方に折曲され略円弧状に突出する下辺折曲部２２とが設けられ、下辺折曲部２２は表底１２と中底１４の間に挟持される。先芯本体部２１は前壁２１ａと、側壁２１ｂ、２１ｃと、天壁２１ｄとを有し、下辺折曲部２２も先芯本体部２１の前壁２１ａと側壁２１ｂ、２１ｃにそれぞれ対応する前方折曲部２２ａと側方折曲部２２ｂ、２２ｃとを有している。また、先芯１１を射出成形する際の金型キャビティのゲートは、前方折曲部２２ａの内縁の略中央部に相当する位置に設けられる。このため、前方折曲部２２ａの内縁には金型のランナーに残存したランナー相当部２３が残されている。
【００１５】
ここで、図４の部分拡大図に示すように、先芯本体部２１と下辺折曲部２２の連接部の交角は略直角とされると共に、連接部の内側、外側のそれぞれの下辺折曲部２２の厚さt1は、先芯本体部２１の下部の厚さt2よりも薄くされている。そして、下辺折曲部２２の後端部の厚さは、先芯本体部２１の下部の厚さt2よりも小さいが、金型のゲートの径よりは大きくされている。
【００１６】
ここで使用する合成樹脂は繊維を加えて強化することが好ましく、合成樹脂にはポリアミド、ポリカーポネイト、ポリプロピレン、ＡＢＳ、ポリウタレン、ポリエチレン、ポリエチレンテレフタレート、エポキシ及びこれら相互の混合品、又はゴムとの混合品を使用することができ、繊維にはガラス繊維、カーボン繊維、ケプラー（商品名）等を使用することができる。
【００１７】
先芯１１を射出成形する際には、合成樹脂を金型のランナーを介してゲートから金型キャビティ内に射出する。このとき、下辺折曲部２２の後端部の厚さが金型のゲートの径よりも大きくされているため、先芯１１の下辺折曲部２２に相当する部分がファンゲートの役割を果し、図５に示すように合成樹脂は拡散した整流となって金型キャビティの先端壁面に衝突する。合成樹脂が金型キャビティの先端壁面に衝突すると、合成樹脂が反流すると共に様々な方向に向かう乱れた流れが発生し、合成樹脂は金型キャビティの壁面で反射しながら乱流となって金型キャビティ内に充満する。これにより、点線で示すような配向性のない先芯１１を製造することができる。
【００１８】
次に、本実施例により製造した先芯１１と従来の方法で製造した比較例の先芯の耐衝撃性と耐圧迫性を、日本工業規格Ｔ８１０１のＬ種試験条件に基づいて試験した結果を表１に示す。ただし、双方ともポリアミド合成樹脂とガラス繊維の配合による材料を使用し、金型ゲートを実施例では前方折曲部２２ａの内縁の略中央に相当する位置に設け、比較例では先芯の本体部後端中央部に相当する位置に設けている。また、実施例の下辺折曲部２２の厚さt1は１．５ｍｍ、ゲートの径は１．５ｍｍ、曲率R1、R2はそれぞれ１ｍｍとしている。
【００１９】

【００２０】
また、衝撃及び圧迫に対する亀裂の発生の有無を表２に示す。ただし、金型ゲートを実施例では前方折曲部２２ａの内縁の略中央に相当する位置に設け、比較例１では先芯本体部の後端中央部に相当する位置に設け、比較例２では先芯本体部の後端側部に相当する位置に設けている。
【００２１】

【００２２】
このように、実施例では先芯１１を成形するための金型ゲートを、先芯１１の下辺折曲部２２の後端縁の略中央部に相当する位置に設け、合成樹脂や繊維に乱流を起こさせたので、合成樹脂や繊維の方向性がなくなると共に、ウエルドラインを無くすことが可能になり、耐圧迫性や耐衝撃性を充足させ、亀裂の発生を防止することができる。また、先芯本体部２１と下辺折曲部２２の連接部の交角は略直角としたため、前壁２１ａと側壁２１ｂ、２１ｃの強度を向上させることができる。
【００２３】
更に、先芯１１を安全靴に装着した際に、金型のランナー相当部２３を表底１２と中底１４の間に隠すことができるため、着用者に対する違和感を与えることがない。そして、ランナー相当部２３を切断したり、切断部を仕上げる必要がないため、製造工程の削減を実現することができる。
【００２４】
なお、曲率R1、R2は０．５〜２ｍｍとしたが、曲率R1、R2を更に小さくすれば合成樹脂を前壁２１ａに衝突させ、乱流を発生させ易くなる。また、下辺折曲部２２の厚さt1が薄いほど乱流を発生し易くなるが、薄過ぎると先芯１１を安全靴に装着し難くなるので、上述した値にすることが好ましい。
【００２５】
【発明の効果】
以上説明したように第１発明に係る安全靴用先芯は、合成樹脂の流れを乱して乱流を起こさせて成型しているので、合成樹脂の結合力を向上させ、ウエルドラインを無くすことができ、耐圧迫性及び耐衝撃性を向上させることができると共に、亀裂の発生を防止することができる。また、金型のランナー部に相当する部分が残存していても品質を損なうことが無いため、仕上工程を無くすることができる上に、ランナー相当部による違和感を与えることはない。
【００２６】
また、第２発明に係る安全靴用先芯の製造方法は、下辺折曲部の後端縁の略中央に相当する位置から、合成樹脂を金型キャビティの前壁に衝突するように射出するので、合成樹脂の流れを乱して乱流を起こす効果を大きくし、よりその配向性をなくすことができる。従って、合成樹脂の方向性がなくなり、耐圧迫性及び耐衝撃性を向上させることができる。
【図面の簡単な説明】
【図１】先芯を備えた安全靴の一部を切欠した断面図である。
【図２】先芯の斜視図である。
【図３】先芯の縦断面図である。
【図４】部分拡大断面図である。
【図５】乱流を起こした合成樹脂の説明図である。
【図６】従来例の先芯の斜視図である。
【図７】耐衝撃性の試験装置の一部の斜視図である。
【図８】従来例の合成樹脂の配向の斜視図である。
【図９】従来例の合成樹脂の配向の斜視図である。
【図１０】従来例の先芯の縦断面図である。
【符号の説明】
１１先芯
２１先芯本体部
２２下辺折曲部
２２ａ前方折曲部
２３ランナー相当部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a safety shoe toe core to be attached to a safety shoe foot to protect the wearer's foot from pressure and impact, and a method of manufacturing the same.
[0002]
[Prior art]
Conventionally, the pressure resistance and impact resistance of this type of safety shoe tip are specified by the Japanese Industrial Standard (JIS). For example, a leather safety shoe for heavy work and normal work uses a metal material, The leather safety shoes for light work are supposed to use a metal material or a synthetic resin material.
[0003]
In general, synthetic resins are often reinforced with fibers, and the tip is formed by injection molding or compression molding using these synthetic resins and fibers. For example, as shown in FIG. 6, the tip core 1 has an arch-shaped tip core main body portion 2 and a lower side bent portion 3 that is bent inward from the lower side of the tip core main body portion 2 and protrudes in a substantially arc shape. Provided. When the tip 1 is injection-molded, a mold gate is often provided at the rear end central portion 2a or the rear end side portion 2b of the tip core main body 2 in order to facilitate molding. Often runners are shortened to take multiple pieces.
[0004]
The core 1 thus molded is subjected to a compression test and an impact test according to Japanese Industrial Standards. The compression test is performed by gradually applying a predetermined load to the tip 1 with a pressure bed (not shown). Further, as shown in FIG. 7, in the impact test, a plunger P having an impact blade C is disposed on the upper surface of the tip 1, and a weight having a predetermined weight is dropped on the plunger P from a predetermined height. Is done.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional example, when a mold gate is provided at the rear end center portion 2a of the tip core main body 2, the synthetic resin or fiber is injected into the tip core in the mold cavity as shown in FIG. 1 flows from the portion corresponding to the top wall of the front core 1 toward the front wall and the side walls corresponding to both side walls, and in the portion corresponding to the both side walls of the front core 1, the flow of the synthetic resin and fibers is oriented in the vertical direction. Become. For this reason, even if the pressure resistance from above is satisfied, since the synthetic resin and fibers are oriented in the same direction as the direction of the impact blade C on the front wall and both side walls, there is a problem that the impact resistance is insufficient. .
[0006]
Further, as shown in FIG. 9, when synthetic resin or fiber is injected from a mold gate provided on the rear end side portion 2 b, the synthetic resin or fiber is transferred from the portion corresponding to one side wall of the tip 1 to the top of the tip 1. It flows toward the portion corresponding to the wall and the front wall, and then flows to the portion corresponding to the other side wall of the lead core 1. For this reason, since the synthetic resin or fiber is oriented in the direction perpendicular to the impact blade C on the top wall, front wall, and both side walls of the tip 1, the impact resistance is satisfied, but the pressure resistance is insufficient. is there.
[0007]
Furthermore, when the mold gate is provided at the rear end center portion 2a and the rear end side portion 2b of the lead core body 2, the synthetic resin or fiber considered to be caused by the shape or thickness of the tip 1 In many cases, a weld line is generated due to the merging, and therefore, there is a problem in that stress is concentrated on the cut portion 5 and cracks occur in the tip 1 when subjected to pressure or impact during use.
[0008]
And after forming the lead core 1, as shown in FIG. 10, it is necessary to cut | disconnect the runner equivalent part 4 which remained in the runner of a metal mold | die in the cutting part 5, and finish it. When this finishing process is not sufficient, there is a problem that the wearer of the safety shoes is uncomfortable or an appearance defect is caused.
[0009]
Further, from the viewpoint of quality, the tip 1 is gradually thinned toward the rear end, but in order to improve the strength, the thickness t of the front wall, the tip core main body 2 and the lower bent portion In some cases, the curvature R of the three connected portions is increased. However, even in this case, there is a problem that the orientation of the synthetic resin or fiber cannot be changed, and the occurrence of weld lines and cracks cannot be prevented.
[0010]
An object of the present invention is to provide a safety shoe toe core that eliminates the above-mentioned problems and eliminates the flow orientation of the synthetic resin to improve pressure resistance and impact resistance, and a method for manufacturing the same.
[0011]
[Means for Solving the Problems]
A tip for safety shoes according to the first invention for achieving the above object is provided with an arch-shaped tip core main body portion for protecting the foot tip by being attached to the foot tip portion, and a lower side of the tip core main body portion. In a synthetic resin safety shoe toe core having an inwardly projecting lower side bent portion that protrudes in a substantially arc shape, the synthetic resin inlet at the time of molding corresponds to the approximate center of the inner edge of the lower side bent portion. The synthetic resin is injection-molded so as to collide with the front wall of the mold cavity from the injection port.
[0012]
A safety shoe toe manufacturing method according to the second aspect of the present invention includes an arch-shaped toe body for attaching to a toe and protecting the toe, and an inner side from the lower side of the toe body. When manufacturing a synthetic resin safety shoe tip having a lower bent portion protruding in an arc shape by injection molding using a mold, it is at a position corresponding to the approximate center of the inner edge of the lower bent portion. The synthetic resin is injected from a mold gate provided so as to collide with the front wall of the mold cavity, and the flow of the synthetic resin is disturbed to cause turbulent flow and molding.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail based on the embodiment shown in FIGS.
FIG. 1 is a cross-sectional view of a safety shoe using a tip 11 according to the present embodiment, in which a part of the safety shoe is cut away. An upper 13 is attached to the top of the outsole 12, and an insole 14 is laminated on the upper surface of the outsole 12, and the bottom of the lead 11 and the upper 13 is sandwiched between the outsole 12 and the insole 14. The front and back 15 are attached to the inner surface of the tip 11.
[0014]
The tip 11 is injection-molded with a synthetic resin material. As shown in the perspective view of FIG. 2 and the longitudinal sectional view of FIG. 3, the tip 11 has an arch-shaped tip core body 21 covering the foot tip and the tip. A lower side bent portion 22 that is bent inward from the lower side of the main body portion 21 and protrudes in a substantially arc shape is provided, and the lower side bent portion 22 is sandwiched between the outsole 12 and the midsole 14. The front core body 21 has a front wall 21a,

side walls

21b and 21c, and a top wall 21d, and the lower bent portion 22 also corresponds to the front wall 21a and the

side walls

21b and 21c of the front core body 21 respectively. It has a bent portion 22a and side bent

portions

22b and 22c. Further, the gate of the mold cavity when the tip 11 is injection-molded is provided at a position corresponding to the substantially central portion of the inner edge of the front bent portion 22a. For this reason, the runner equivalent part 23 which remained in the runner of the metal mold | die is left in the inner edge of the front bending part 22a.
[0015]
Here, as shown in the partially enlarged view of FIG. 4, the intersection angle of the connecting portion of the tip core main body portion 21 and the lower side bent portion 22 is substantially a right angle, and the lower side bends on the inner side and the outer side of the connecting portion, respectively. The thickness t1 of the portion 22 is made thinner than the thickness t2 of the lower portion of the tip core main body portion 21. The thickness of the rear end portion of the lower bent portion 22 is smaller than the thickness t2 of the lower portion of the lead core main body portion 21, but larger than the diameter of the gate of the mold.
[0016]
The synthetic resin used here is preferably reinforced by adding fibers, and the synthetic resin is composed of polyamide, polycarbonate, polypropylene, ABS, polyutalene, polyethylene, polyethylene terephthalate, epoxy, a mixture of these, or rubber. A mixed product can be used, and glass fiber, carbon fiber, Kepler (trade name) or the like can be used as the fiber.
[0017]
When the tip 11 is injection-molded, synthetic resin is injected from the gate into the mold cavity through a mold runner. At this time, since the thickness of the rear end portion of the lower side bent portion 22 is larger than the diameter of the gate of the mold, the portion corresponding to the lower side bent portion 22 of the lead core 11 serves as a fan gate. As shown in FIG. 5, the synthetic resin collides with the tip wall surface of the mold cavity as diffused rectification. When the synthetic resin collides with the tip wall of the mold cavity, the synthetic resin counter-currents and a turbulent flow in various directions is generated, and the synthetic resin is reflected by the wall of the mold cavity and becomes a turbulent flow. Fill the mold cavity. Thereby, the tip 11 without orientation as shown by a dotted line can be manufactured.
[0018]
Next, the results of testing the impact resistance and pressure resistance of the tip 11 manufactured according to the present embodiment and the tip of the comparative example manufactured by the conventional method based on the L-type test conditions of Japanese Industrial Standard T8101. Table 1 shows. However, both use materials made of a blend of polyamide synthetic resin and glass fiber, and the mold gate is provided at a position corresponding to the approximate center of the inner edge of the front bent portion 22a in the embodiment, and the main body portion of the lead core in the comparative example It is provided at a position corresponding to the central portion of the rear end. Further, the thickness t1 of the lower bent portion 22 of the embodiment is 1.5 mm, the gate diameter is 1.5 mm, and the curvatures R1 and R2 are each 1 mm.
[0019]

[0020]
In addition, Table 2 shows whether or not cracks are generated due to impact and compression. However, in the embodiment, the mold gate is provided at a position corresponding to the approximate center of the inner edge of the front bent portion 22a. In Comparative Example 1, the mold gate is provided at a position corresponding to the center of the rear end of the lead core main body. It is provided at a position corresponding to the rear end side portion of the tip core main body portion.
[0021]

[0022]
Thus, in the embodiment, the mold gate for forming the tip 11 is provided at a position corresponding to the substantially central portion of the rear edge of the lower side bent portion 22 of the tip 11 to disturb the synthetic resin or fiber. Since the flow is caused, the directionality of the synthetic resin and fiber is lost, and the weld line can be eliminated, the pressure resistance and the impact resistance are satisfied, and the occurrence of cracks can be prevented. In addition, since the intersection angle of the connecting portion of the tip core main body 21 and the lower bent portion 22 is substantially a right angle, the strength of the front wall 21a and the

side walls

21b and 21c can be improved.
[0023]
Furthermore, since the runner equivalent part 23 of a metal mold | die can be hidden between the outsole 12 and the insole 14 when the tip 11 is attached to safety shoes, it does not give the wearer a sense of incongruity. And since it is not necessary to cut | run the runner equivalent part 23 or finish a cut part, reduction of a manufacturing process is realizable.
[0024]
In addition, although curvature R1, R2 was 0.5-2 mm, if curvature R1, R2 is made still smaller, a synthetic resin will be made to collide with the front wall 21a, and it will become easy to generate | occur | produce a turbulent flow. Further, the smaller the thickness t1 of the lower bent portion 22, the easier it is to generate turbulence. However, if the thickness is too thin, it becomes difficult to attach the tip 11 to the safety boot, so the above-mentioned value is preferable.
[0025]
【The invention's effect】
As described above, the tip for safety shoes according to the first invention is molded by disturbing the flow of the synthetic resin to cause turbulence, thereby improving the binding force of the synthetic resin and eliminating the weld line. It is possible to improve pressure resistance and impact resistance and to prevent generation of cracks. Further, even if a portion corresponding to the runner portion of the mold remains, the quality is not impaired, so that the finishing process can be eliminated, and a sense of incongruity due to the runner corresponding portion is not given.
[0026]
Moreover, the manufacturing method of the tip for safety shoes which concerns on 2nd invention inject | pours a synthetic resin from the position equivalent to the approximate center of the rear-end edge of a lower part bending part so that it may collide with the front wall of a metal mold cavity. Therefore, the effect of causing the turbulent flow by disturbing the flow of the synthetic resin can be increased, and the orientation can be further eliminated. Accordingly, the directionality of the synthetic resin is lost, and the pressure resistance and impact resistance can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in which a part of a safety shoe having a tip is cut out.
FIG. 2 is a perspective view of a lead core.
FIG. 3 is a longitudinal sectional view of a tip.
FIG. 4 is a partially enlarged cross-sectional view.
FIG. 5 is an explanatory view of a synthetic resin causing turbulent flow.
FIG. 6 is a perspective view of a conventional lead core.
FIG. 7 is a perspective view of a part of the impact resistance test apparatus.
FIG. 8 is a perspective view of the orientation of a conventional synthetic resin.
FIG. 9 is a perspective view of the orientation of a conventional synthetic resin.
FIG. 10 is a longitudinal sectional view of a conventional lead core.
[Explanation of symbols]
11 tip core 21 tip core main body part 22 lower side bent part 22a front bent part 23 runner equivalent part

Claims

Made of synthetic resin having an arch-shaped toe body for attaching to the toe and protecting the toe, and a lower bent part projecting in a substantially arc shape inward from the lower side of the toe body In the safety shoe tip, the synthetic resin injection port at the time of molding is provided at a position corresponding to the approximate center of the inner edge of the lower bent portion, and the synthetic resin is fed from the injection port to the front wall of the mold cavity. A tip for safety shoes, which is injection-molded so as to collide.

The safety shoe front core according to claim 1, wherein the connecting portion between the front core main body portion and the lower bent portion is bent at a substantially right angle with a small curvature on the outside.

The tip for safety shoes of Claim 1 which mix | blended fiber with the said synthetic resin.

Safety made of synthetic resin having an arch-shaped tip core main body for attaching to the tip of the foot and protecting the tip of the toe, and a lower bent portion protruding in a substantially arc shape from the lower side of the tip core main body In the case where a shoe tip is manufactured by injection molding using a mold, the synthetic resin is applied to the front wall of the mold cavity from a mold gate provided at a position substantially corresponding to the center of the inner edge of the lower bent portion. A method for manufacturing a toe core for safety shoes, characterized in that injection is performed so as to collide and molding is performed by causing turbulence by disturbing the flow of the synthetic resin.

The thickness of the said lower side bending part is more than the diameter of the said mold gate, and is less than the thickness of the said front-end | tip front part, The manufacturing method of the front-end for safety shoes of Claim 4.